LHC wire scanners status BI/TB 05/03/2015 E. Piselli – B. Dehning – J. Emery BE-BI-BL

Outline LHC wire scanners LS1 mechanical upgrades Electronics Photomultiplier studies New operational application

LHC wire scanners 8 linear wire scanners installed (4 spares) Beam 2 2 scintillators, filters and photomultipliers Fast acquisition Max speed: 1m/s Wire size: 30μm Aperture: 60mm Beam 2 Beam 1

LS1 mechanical upgrades Pre LS1 bellows had experienced few vacuum leaks and the maximum rating given by the manufacturer was 10000 scans. During LS1 all bellows were exchanged but different stiffness and vacuum force of the new ones required new compensation springs. The new bellows have been validated by calculation (P.Magagnin) and by functional observation with 1000 scans.

LHC BWS Firmware (board with 3 FPGA) Electronics LHC BWS Firmware (board with 3 FPGA) Same running version in the PSB and PS since 15.09.2009 and in LHC since 2010. Intensive use in CPS has shown its limitations. Firmware release mandatory in order to: 1) Have a safe InitHW sequence (return from IN position) 2) Add extra safety necessary to avoid the ‘reset home problem’ 3) Mitigate about 1% of ‘lost Triggers ‘ 4) Be able to move the scanner to the home position from any position

Electronics Where we are… Firmware Status: Next Steps: Lost triggers Firmware bug identified & fixed New version tested in lab Safe Init Hardware Sequence Successfully tested in lab Extra safety to avoid failure during Init Hardware Inhibit relay to be switched ON if position difference too large Next Steps: Deploy new firmware on full CPS-type scanner test installation in 867 Two weeks of extensive testing with the new firmware for all identified failure scenarios Deployment in LHC to be planned…

Photomultiplier studies PHILIPS XP2243B voltage divider phototube

Photomultiplier studies Signal OUT K A D1 D2 D3 D4 D5 D6 10KΩ 3R R R R 1.5R 470KΩ 680KΩ C1 C1 C1 C1 C1 C1 C1 C2 C2 C2 C3 R=220KΩ C1=10nF C2=112nF C3=39nF -HV

Photomultiplier studies We have studied the response linearity of the photomultiplier... Visible saturation from measurements...

Photomultiplier studies Lab setup Freq. generator 1Hz Oscilloscope Green led diode K A Signal OUT 50Ω -HV

Photomultiplier studies We have performed different measurements: @ 1800V and 2000V @ different output current…1mA, 2mA and 5mA @ different pulse width…500μs, 1ms, 2ms, 5ms, 10ms and 20ms (always 1Hz frequency) 2000V 1mA 500μs 2000V 3mA 2ms 2000V 5mA 5ms

Photomultiplier studies Hamamatsu PMT specification in dynamic mode (ns scale): To achieve 1% linearity Q*=100·Qsignal Qsignal K A We have added 3 decoupling capacitors (15μF each) in parallel to the 3 last ones in order to: supply photomultiplier tube with an electric charge during the forming of the signal pulse restrain the voltage drop between the last dynode and the anode

Photomultiplier studies Signal OUT K A D1 D2 D3 D4 D5 D6 10KΩ 3R R R R 1.5R 470KΩ 680KΩ C1 C1 C1 C1 C1 C1 C1 C2 C2 C2 C3 R=220KΩ C1=10nF C2=112nF C3=39nF -HV 13

Photomultiplier studies Signal OUT K A D1 D2 D3 D4 D5 D6 10KΩ 3R R R R 1.5R 470KΩ 680KΩ C1 C1 C1 C1 C1 C1 C1 C2 C2 C2 C3 C4 C4 C4 R=220KΩ C1=10nF C2=112nF C3=39nF C4=15μF -HV

Photomultiplier studies 2000V 1mA 500μs 2000V 3mA 2ms 2000V 5mA 5ms

Photomultiplier studies B1 and B2 PM have been reinstalled in the machine…

Photomultiplier studies We have few consequences after the modifications done to the system: When HV is applied for the first time we have to wait about 30sec HV will be left ON after each scan at least for 30’ Front end and application software needs to be modified New studies will be performed using laser diode to verify linear response of PM output signal with light intensity We are investigating on new PM

New operational application Developed by M.Kuhn

New operational application Can acquire data after a scan or get data from logging or measurement DB. Emittance evolution through a fill (either bunch-by-bunch emittance or average emittance per scan depending on number of bunches). Displays the bunch-by-bunch transverse profiles. Displays bunch-by-bunch emittances per scan in a bar graph. Developed by M.Kuhn and V.Kain 19

New operational application User can scroll through bunch profiles and different scans. All wire scanners in one application (scroll down). Developed by M.Kuhn and V.Kain

New operational application First fitting done in front end. Analyse button to fit the profiles with a five parameter Gauss. Common java package in all accelerators for fitting. Fit data will be send to logging database. Developed by M.Kuhn and V.Kain

New operational application User can choose between nominal beta function or measured beta function (stored in LSA) for emittance calculation. Developed by M.Kuhn and V.Kain

New operational application Number of bunches automatically chosen from sequencer. All circulating bunches are selected by default. Updated automatically. There is also a possibility to manually select or deselect bunches (in configure bunch selection). Developed by M.Kuhn and V.Kain

New operational application Particle type is always monitored via LSA. Application also works for ions now! Developed by M.Kuhn and V.Kain

New operational application In “configure scanners” voltage and filter of PMs can be set. Predefined settings can be uploaded. New gain scale: gain now in per mille! In “configure acquisition” wire scanners can be enabled and disabled for a scan. Future possibility to launch multiple scans. Scan button is pressed only once and all enabled scanners are fired one after the other. Scanner status is always monitored. Photomultiplier saturation (colour coded) to be implemented after calibration. Developed by M.Kuhn and V.Kain

Thanks for you attention… Conclusion All the wire scanners have been refurbished with new bellows and all the springs have been adapted differently for the horizontal and vertical axes New firmware should avoid difficult situations observed in the past PM have been modified for the saturation problems Operational GUI is easier and complete Commissioning and MD time have been requested People involved: P. Magagnin, R. Veness, A. Guerrero, M. Kuhn, L. Timeo Thanks for you attention…